Licence: In copyright
Credit: The plant alkaloids / by Thomas Anderson Henry. Source: Wellcome Collection.
Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.
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![partial separation of tLe alkaloids is effected ; purification may be completed by fractional crystallisation of the aurichlorides. For this purpose the two portions are dissolved sej)arately in a slight excess of dilute hydrochloric acid, and the aurichlorides precipitated in fractions by adding solution of gold chloride. These fractions are recrystallised from hot water containing a little hydrochloric acid and the process repeated until fractions of constant melting-point are obtained. Atropine aurichloride separates as an oil, but be- comes crystalline on standing, and on recrystallisation melts at 136°. It liquefies when heated in water. Hyoscyamine auri- chloride is usually precipitated in crystalline form, and when pure melts at 162°. bScopolamine aurichloride is also precipitated as a rule in crystals, and when recrystallised till pure melts at 198°.^ Estimation of the Total Alkaloids of Solanaceous Plants As already indicated, the solanaceous plants yielding hyoscya- niine and scopolamine are of great importance as drugs, or as sources of atropine and the other alkaloids of this group. Certain members of this group of plants are recognised in the various national pharmacopoeias, and in most cases the official galenical preparations made from them are “ standardised,” i.e. at certain stages in their manufacture the preparations are assayed for alkaloids by prescribed processes and then concentrated or diluted until their alkaloidal contents agree with prescribed standards. Some of the principal official assay processes for these drugs and their preparations are as follow : The crude drugs of this class recognised in the British Pharma- copoeia are henbane leaves {Hyoscyamus belladonna leaves and roots [Atropa Belladonna), and stramonium leaves and seeds [Datura Stramonium). The Pharmacopoeia does not prescribe methods for the assay of the crude drugs. The following processes devised by 1 For further information on the isolation, purification, and identification of these alkaloids, see Dunstan and Chaston, Pharm. Journ. 1889 [iii], 20,461; Dunstan and Brown, 'Trans. Chem. Soc. 1899, 75, 72 ; 1901, 79, 71 ; Andrews, ibid. 1911, 99, 1871 ; Carr and Reynolds, ibid. 1912, 101, 957.](https://iiif.wellcomecollection.org/image/b2196189x_0064.jp2/full/800%2C/0/default.jpg)
